Telephone system



7 Sept. 15, 1925. 1,553,317

' E. E. HINRICHSEN TELEPHONE SYSTEM Filed Sept. 18, 1923 2 Sheets-Sheet 1 u u Illa-m y Al Sept. 15, 1925. 1,553,317

E. E. HINRICHSEN TELEPHONE SYSTEM Filed Sept. 18, 1923 2 Sheets-Shier. 2

Fig. 2

//7 van/0r Patented Sept. 15, 1925.

UNITED STATES PATIENT OFFICE.

EDWARD E. HINRICHSEN, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

To all whom it may concern:

Be it known that I, EDWARD E. HINRICH- SEN, a citizen of the United States of America, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone systems and particularly to automatic systems of small capacity such as are used for private branch exchange working. I

The object of the invention is to produce a simple, cheap and eflicient system using the least amount of apparatus possible.

In accordance with the above object the selecting means which is responsive to dial impulses is eliminated from the link circuit and a circuit is arranged so that the connecting relays will perform the selecting function in addition to their usual connecting function.

A feature of the invention is the use of a divided path from the link circuit to the connecting relays whereby the odd and even relays are effectively separated during the dialing operation and momentary connections between adjacent lines is thereby prevented.

The invention is illustrated by two figures, which when placed Fig. 2 to the right of Fig. 1 show diagrammatically the preferred circuit arrangement embodying the invention.

Fig. 1 shows a number of subscribers lines with the finder and connector relays for two associated link circuits. Fig. 2 shows a link circuit which may be matched with either the upper or lower link circuits of Fig. 1. When the figures are placed in the position indicated, the link circuit of Fig. 2 will match with the upper link circuit of Fig. 1, and we will therefore assume for purposes of illustration that the lower link circuit is busy. When a link circuit is busy, its associated starter relay is operated, and thus in the present case we will assume that the relay 4 is energized.

According to the present arrangement, the link circuits are used in turn and a circuit arrangement is provided to insure even discircuit.

tribution of traflic. Thus, when relay 4 becomes energized it is locked into a circuit from ground back contact and armature of relay 7, through the inner right hand armature and front contact and right hand winding of relay 4 to battery and ground. This condition is maintained even after the link circuit becomes idle. The next call will therefore be switched through relay 5, and when this relay becomes energized, it also is locked to the ground provided at the armature of relay 7. When the last link cir-' cuit is taken for use a circuit is completed from ground through the front contacts and armature and front contact of relay 8, the

left hand armature and front contact of relay 4, the left hand armature and back contacts of relay 5 to the windings of relays 9 and 10 in parallel and thence to battery and ground. Through the energization of relay 9 the finder relay 11 ofthe link circuit associated with relay 5 and individual to line 1 is energized. Thus, a circuit is completed from ground, the right hand armature and front contact of relay 8, the front contact and inner left hand armature of relay 9,

winding of relay 11 to battery and ground.

Relay 11 immediately locks up in a circuit from ground, left hand armature and front contact of relay 10, front contact and right hand armature of relay 11, winding of relay 11 to battery and ground. Relay 11 in operating causes the energization of the cut-off relay 12 through a circuit from ground, inner left hand armature and front contact of relay 11, winding of cut-off relay 12 to battery and ground. The energization of relay 12 causes the deenergization of the line relay 8.

In the meantime the line of substation 1 has been extended through the contacts of finder relay 11 to the windings of impulse relay 13, Which, becoming operated, causes the energization of relay 14 and relay 5 in series through a circuit extending from ground, armature and front contact of relay 13, inner right hand armature and back cont-act of relay 15, normal contacts of the right hand armature of relay 14, Winding of relay 1'4, left hand Winding of relay 5 to battery and ground. This circuit is then maintained through the right hand armature of relay 10. Relay 5 becomes operated to switch other incoming calls to other link circuits. Relay 14 becomes operated to assume control of the link circuit of Fig. 2 by placing a ground on conductor 16 through its left armature and the normal contacts of the left hand armature of relay 17. The ground on conductor 16 is noW extended to the Winding of relay 18 through a circuit extending from ground on conductor 16, the back contact and left hand armature of relay 19,- the back contact and outer right hand armature of relay 20, Winding of relay 18 to battery and ground. Relay 18 causes the operation of relay 21, the circuit for relay 21 extending from; ground on conductor 16 through the front contact and left hand armature of relay 18, Winding of relay 21 to battery and ground. A substitute circuit for relay 10 is noW com pleted from ground, armature and front contact of relay 13, inner right hand armature and back contact of relay 15, alternate con tacts of the right hand armature of relay 14, front contact and outer left hand armature of relay 21, Winding of relay 10 to battery and ground. The link circuit is now in a stable condition awaiting the sending of impulses from the subscribers line.

o Will assume for purposes of illustration that the subscriber at substation 1 Wishes to extend a connection to substation 3, and that this substation is reached through the dialing of three impulses. Each of these impulses is in the form of a short interruption of the calling subscribers line circuit and results in the momentary deenergization of relay 13'. Upon the first deenergization of this relay, a circuit is extended from ground, armature and back contact of relay 13, front contact and inner left hand armature of relay 21, and thence to a point Where the circuit divides, extending in one direction through the Winding of slow rel asing relay 22 to battery and ground, and in the other direction through the inner left hand armatures and back contacts of relays 24, 25 and 26, Winding of connecting relay 27 to battery and ground. Connecting relay 27 is energized in this circuit and prepares a circuit 'for relay 26 extending from the Winding of relay 26 through the right hand armature and front contact of rela 27, the back contact and outer left hand armature of relay 25, the right hand armature and front contact of relay 22 to the ground on conductor 16. Since relay 26 is short circuited at this time it does not become energized but when the armature of relay 13 is attracted after the momentary impulse, relay 26 energizes in series With relay 27. An instant later ground Wlll be placed on the loft hand armature of relay 26 and this Will now be extended through the front contact of relay 26 to the Winding of relay 28, causing the energization of this latter relay. It will be noted at this point that for an instant relays 27 and 28 are both energized, and should the front contacts of their left hand armatures both lead to'the same path into the link circuit, lin'esl and 2 would be momentarily connected together, but in the present arrangement, providing as it does, a split path from the odd and even relays of the link circuits, such interconnection of subscribers lines is impossible. Upon the energization of relay 28, a circuit is prepared for the energization of relay 25 so that upon the ending of this second impulse, relay 25 will become energized in se ries With relay 28. The energization of relay 25 opens the circuit for relays 26 and 27 so that they now become deenergized. In a similar manner, the third impulse causes the energization of relay 29, and upon the ending of the impulse, the 'energization of relay 24 and the consequent deenergization of relays 25 and 28. Shortly after the sending of this series of impulses, the slow releasing relay 22 becomes deenergized, whereupon a circuit for relay 19 is completed from ground on conductor 16 through the front contact and inner right hand armature of relay 21, the back contact and left hand armature of relay 22, the right hand armature and front contact of relay 24, Winding of relay 19 to battery and ground. Relay 19 connects the sleeve conductor of the called line through its front contacts and right hand armature to the testing relay 17 so that if the called line 3 is busy, a ground Will be extended over its third conductor through the front contact and right hand armature of relay 19, the right hand armature and front contact of relay 18, the right hand winding of relay 17 to battery and ground,

causing the energization of this relay. Relay 17 becoming energized, connects the source of busy tone 30 through its front con tact and right hand armature, the condenser 31, the right hand Winding of relay 32 to battery and ground, whence through induction busy tone is transmitted to the calling subscriber. When relay 17 becomes energized it looks up through its left hand armature to the ground supplied at the left hand armature of relay 14 and cuts ofi ground from conductor 16'. The removal of ground from conductor 16 allows con lot) nectingrelays 24 and 29, and the link relays 18, 19 and 21 to become deenergized. Relay 10 is maintained energized through the resistance 33, which is bridged around the contacts of the outer left hand armature of relay 21, thus supplyingsuflicient current to cause the continued energization of this holding relay. Relay 10, in turn, maintains relays 14 and 5 energized, and as long as relay 14 remains: energized, relay 17 re-.

mains locked up so that busy tone is transmitted to the calling subscriber until he replaces his receiver on its hook and causes the deenergization of the holding. relay 10.

If, on the other hand, the called line 3 is idle, then the battery of the cut-01f relay will be opposed to the battery of the testing relay and relay 17 will not become energized. Instead, a circuit will be completed for relay 20 extending from ground on conductor 16 through the front contact and outer right hand armature of relay 21, the left hand armature and front contact of relay 19, winding of relay 20 to battery and ground. Relay 2O attracts its armatures and locks up through its inner right hand armature to the ground on conductor 16, this locking circuit extending, through the armature and back contact of ringing cutolf relay 34. It should be noted that upon the energization of relay 19 the circuits described for the energization of relays 17 and 20 are simultaneously closed and these relays both become operated if the line is busy, but if the line is busy, then relay 17 by cutting off ground from conductor 16 and releasing relay 21 causes the immediate deenergization of relay 20. If the line is idle, however, relay 17 does not become operated at all and relay 20 thereupon locks up in the circuit described to. the ground on conductor 16. The operation of relay 20 opens the circuit of relay 18, which in turn opens the circuit of relay 21 so that relay 35 now is included in a circuit in series with relay 19, such circuit extending from ground on conductor 16 through the winding of relay 35, the back contact and left hand armature of relay 22, the right hand armature and front contact of relay 24, winding of relay 19 to battery and ground. Relay 35 becomes energized and completes a connection from the called line to the contacts of the ringing relay 20, whereupon ringing current is extended from the source of ringing current 36 through the ringing cut-off relay 34, the front contact and the outer left hand armature of relay 20, the inner right hand armature and front contacts of relay 35, the front contact and middle left hand armature of relay 29 over the loop of called substation 3, the outer left hand armature and front contact of relay 20, the front contacts and outer right hand armature of relay 35, the inner left. hand armature and front contact of relay 20 to ground. In this circuit the current is insufficient to cause the energization of relay 34 until the called subscriber removes his receiver from its hook, whereupon relay 34 becomes energized, and opening the locking circuit of relay 20, causes the ringing current to be cut-off and the talking circuit to be extended through the back contacts and right hand armatures of relay 20 to the calling subscribers line. The called subscriber now has control over the called supervisory relay 32, which, be-

coming energized, assumes a measure of control over the relay 14.

At the end of the conversation, 'when both subscribers hang up their receivers and the calling supervisory relay 13 and the called supervisory relay 32 become deenergized, the link circuit is returned to normal and the connection between substations 1 and 3 is broken.

In case the calling subscriberhangs up his receiver first, the release of relay 13 releases relay 10, which in turn releases the operated relay 11 and frees the calling line. Relay 32, however, remains operated and keeps relays 14 and 5 energized so that the link circuit remains connected to the called line until the called subscriber has hung up his receiver, and while so connected this link circuit cannot be taken by an originate ing call.

What is claimed is:

1. In a telephone system, telephone lines, a link circuit, relays for connecting said link circuit to said lines, said relays being arranged to respond in succession to dial impulses, and means to prevent the interconnection of said lines when a plurality of said relays are simultaneously energized.

2. In a telephone system, telephone lines, a link circuit, relays for connecting said link circuit to said lines, two channels from said link circuit to said relays, alternate relays being associated with different channels, said relays being arranged to respond in succession to dial impulses, and means for separating said channels during the dialing period whereby momentary interconnections between said lines are prevented.

3. In a telephone system, telephone lines, a link circuit, relays for connecting said link circuit tosaid lines, said relays being arranged to act as counting relays, separate channels from the link circuit being provided for the odd and even relays, and means operable upon the completion of the counting operation to connect said separate channels together.

4. In a telephone system, telephone lines, link circuits, relays for connecting said link circuits to said lines, said relays being arranged to respond in succession to dial impulses, and means to prevent momentary interconnections between said lines when a lac plurality of said relays have their armatures simultaneously attracted.

5. In a telephone system, telephone lines, link circuits, a set of relays individual to each link circuit for connecting said link circuit to said lines, said relays being arranged to successively respond to dial impulses and means to prevent momentary interconnections between said lines when a plurality of said relays have their armatures 10 simultaneously attracted.

In Witness Whereofi, l hereunto subscribe my name this 12th day of September A. 1)., 1923.

EDWARD 13. HINRIc sE 

